The Telecommunications Industry Association is a trade association accredited by ANSI (American National Standards Institute). In 2005 it published ANSI/TIA-942, Telecommunications Infrastructure Standard for Data Centers, which defined four levels (called tiers) of data centers in a thorough, quantifiable manner. TIA-942 was amended in 2008 and again in 2010.
Microsoft Datacenter
describes the requirements for the data center infrastructure. The simplest is a Tier 1 data center, which is basically a server room, following basic guidelines for the installation of computer systems. The most stringent level is a Tier 4 data center, which is designed to host mission critical computer systems, with fully redundant subsystems and compartmentalized security zones controlled by biometric access controls methods. Another consideration is the placement of the data center in a subterranean context, for data security as well as environmental considerations such as cooling requirements.
The German Datacenter star audit programme uses an auditing process to certify 5 levels of “gratification” that affect Data Center criticality.
Independent from the ANSI/TIA-942 standard, the Uptime Institute, a think tank and professional-services organization based in Santa Fe, New Mexico, has defined its own four levels on which it holds a copyright. The levels describe the availability of data from the hardware at a location. The higher the tier, the greater the availability. The levels are:
| Tier Level | Requirements |
|---|---|
| 1 |
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| 2 |
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| 3 |
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| 4 |
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